1. Field of the Invention
This invention relates to treatment of tissue in the urinary, digestive, respiratory, reproductive and circulatory systems. Such treatment can be performed using ablation, coating, expansion, plumping, shaping, shrinking, or related techniques.
2. Related Art
Human beings and other animals such as livestock and small animals are subject to a number of disorders that affect the digestive, urinary, respiratory, circulatory and reproductive systems. Frequently, these disorders (such as urinary and fecal incontinence) involve the relative tone of sphincters and other muscles. Other disorders (such as aneurysms) involve changes in the integrity of the wall of an artery or other body structure. Still other disorders (such as cancers, hemorrhoids and pilonital cysts) involve uncontrolled or improperly regulated growth of tissue. Many other disorders, particularly reproductive disorders, involve occlusions in otherwise healthy tissue.
Known methods for the treatment of these disorders include surgery, pharmaceutical remedies, chemotherapeutic regimens, radiation, photodynamic therapy and lifestyle modification. These methods only occasionally achieve the goal of successful treatment of disorders in circulatory, urinary, respiratory, reproductive and digestive systems. Moreover, these methods suffer from several drawbacks.
Drawbacks to surgical treatment include its highly invasive nature, associated risks, possible iatrogenic effects, and high cost. Drawbacks to pharmaceutical and chemotherapeutic treatments include their relative ineffectiveness (particularly in the oral cavity and adjacent respiratory structures) and associated side effects. Moreover, these approaches are contraindicated for many patients. Drawbacks to lifestyle modification include relatively poor patient compliance and relative ineffectiveness. Drawbacks to photodynamic therapy include its frequent unavailability and limited applicability. Drawbacks to radiation include side effects such as exhaustion, radiation burns, chronic dry mouth and permanent distortion of the taste buds. Accordingly, it would be advantageous to provide techniques for treatment of these disorders that are not subject to these known drawbacks.
The use of radio frequency (RF) to ablate tissue in the body (such as heart muscle tissue) is known in the art of cardiac treatment. However, known systems that rely on RF energy are still subject to several drawbacks. One drawback is that it can be difficult to target very small areas of tissue for treatment without causing thermal damage to adjacent structures.
A second problem involves controlling the flow of bodily fluids and gases into an area of the body where tissue ablation is taking place. Controlling the flow of bodily fluids and gases is critical because they can dissipate and detrimentally absorb the energy to be applied to the tissue to be ablated.
A third problem in the art involves directing and positioning the electrodes in the body cavity or orifice. Difficulties in accurately positioning the electrodes in the target orifice detract from treatment. Frequently, unhealthy tissue remains untreated while healthy tissue is removed. Difficulties in directing and positioning the electrodes are particularly problematic because one of the goals of treatment is to minimize collateral damage to healthy tissue and to completely ablate diseased tissue.
A fourth problem in the art involves difficulty in the simultaneous use of complimentary technology. Known systems do not provide for optimal, simultaneous use of auxiliary tools for nerve stimulation, visualization, feedback technology and drug administration.
A fifth problem in the known art involves the simultaneous heating and cooling of adjacent tissues. Frequently, it is desirable to prevent thermal damage to adjacent tissues. One way of preventing such damage is by controlling the temperature of the adjacent tissues. Known systems to not provide for the simultaneous heating and cooling of adjacent tissues.
A sixth problem in the known art involves conforming the interior of an organ such as a bladder to as to be in optimal contact with the electrodes. This inability makes it difficult to predict with any accuracy the overall degree of shrinkage that may result from RF treatment.
Accordingly, it would be advantageous to provide improved techniques for treatment of disorders in the circulatory, respiratory, urinary, digestive and reproductive systems. For example, it would be advantageous to provide devices bearing different arrays of curvilinear or straight electrodes such that each electrode is surrounded by saline. It would be particularly advantageous if such devices could also support apparatus for drug administration and tissue visualization. Such devices would allow medical personnel to (1) visualize the tissue to be treated, (2) seal off the area from fluids and gases that would disturb the area to be treated, (3) target very small areas for treatment, (4) treat all diseased tissue while sparing healthy tissue and (5) provide for the localized administration of drugs to numb the area and treat the disorder. These advantages are achieved in an embodiment of the invention in which medical personnel use a catheter bearing multiple controls for visualization and drug administration, balloon-like air sacs for sealing the area and multiple arrays of curvilinear or straight electrodes that extend out of a holes in a multiporous balloon.
In one aspect of the invention, an environment proximate to or surrounding the targeted treatment region can be isolated or controlled by blocking the flow of gases or liquids using an inflatable, microporous balloon positioned immediately adjacent to the tissue that is to be ablated. The inflatable microporous balloon also serves to anchor the catheter in place and prevent the catheter from being expelled from-the body. The inflatable microporous balloon can also insure that locally administered drugs remain in the area where most needed.
In a second aspect of the invention, straight or curvilinear electrodes emerge out of small apertures in the balloon. Inflation of the balloon with liquid from a constantly circulating bath of chilled fluid has the effect of cooling tissue, including tissue that is immediate adjacent to tissue in direct contact with an electrode. This permits treatment of small, discrete regions while minimizing collateral damage to immediately adjacent structures.
In a third aspect of the invention, the electrodes are coupled to sensors that measure properties of the target region such as temperature, impedance and nervous activity. These measurements are useful both in making diagnostic assessments as well as in determining treatment parameters. Moreover, they can be used to provide for nervous stimulation and/or blocking, and permit the use of feedback technique to control delivery of the RF energy.
In a fourth aspect of the invention, the catheter includes an optical path that can be coupled to external viewing apparatus. A wide variety of endoscopic methods, including fluoroscopic, fiber optic, or radioscopic techniques can be used to examine tissue and determine the position of the electrodes in the body.
In a fifth aspect of the invention, the catheter includes suction apparatus. This suction apparatus can be used to draw away liquids that obscure the treatment area and to gently conform the treatment area to the electrode.